“Dennis absolutely lights up a room. He’s larger than life,” says interior designer Kenneth Alpert of Dennis Basso, his friend and client for 35 years. “If you wake up in a bad mood, you should call Dennis. He’s like a vitamin B-12 shot.”

An eye for glamour and unflagging energy have made Dennis Basso a brand name, with a 10,000-square-foot flagship store on New York’s Madison Avenue and boutiques around the world. In his 30-year-plus career, Dennis has dressed many of the world’s most famous and beautiful women in gowns and furs, including Elizabeth Taylor, Glenn Close, Jennifer Lopez, and Sofia Vergara, whose ample curves are accented by one of his furs in a recent Vanity Fair cover story.

In addition to his couture, the fashion designer has a bridal collection, a line of ready-to-wear, and even home accessories—including sumptuous faux fur throws sold on the QVC shopping channel. (A TV natural, Dennis appears regularly to present his collections.)

Taking a break from this harried pace means heading to the Hamptons home in Water Mill, New York, that he shares with husband Michael Cominotto. Don’t expect to find either one lounging by the pool, though. Their idea of relaxation might involve hosting a dinner party for 40, an impromptu cocktail hour by the outdoor fireplace, or spiffing up guest rooms with bouquets of hydrangeas fresh from the backyard for their frequent weekend guests. “We love to entertain, and for us it’s not work. It gives us great pleasure,” Dennis says with all sincerity in his wonderfully deep gravelly voice. “One of my friends tells me the house has been coined Hôtel du Cap for the service we provide. And we do want to make our guests feel as comfortable as possible.”

Blue-and-white ceramics are displayed in an intimate sitting area between the living and dining rooms.

While Alpert was the interior designer for the projects, he readily shares credit with Dennis. “When we did the kitchen, Dennis came to me with the inspiration. He wanted black-and-white checkerboard floors and a very white kitchen,” says Alpert. The gallery hallway was Dennis’s vision, too, modeled after something similar in a magazine.

“That’s what makes working with Dennis so great. You give Dennis a platform and he runs with it,” Alpert says. The designer focuses on selecting furnishings, fabrics, paint colors, and wallcoverings, and Dennis takes over accessorizing.

Three oversize Charles Edwards light pendants that Dennis found in London hang from the wood plank tray ceiling.

Dining room walls are sheathed in horizontal wood planks painted white, a treatment that adds a casual feel to the beach house and provides a clean backdrop for the deep blue chairs and accessories.

Many furnishings are custom made, including a dining table that can be configured multiple ways to host any number of guests. “The table breaks apart and can become three tables that seat 12 or four tables that seat eight,” says Dennis. “We can bring in some additional round tables, and we have our own mahogany ballroom chairs. We’ve been able to seat up to 62 people in that dining room.

“We’ve done a lot of celebrating in this house—Christmases to engagements to birthdays to dinners for no reason,” he adds.

A pair of 1890s wrought-iron chandeliers hang above the custom table. Chairs are covered in a Nancy Corzine fabric. The Italian carved-wood dolphin plant stands date from the 1920s.

Walls in the master bedroom and library are covered in grass cloth and raffia, giving the rooms a warm, cozy vibe. Arm chairs with faux fur throws sit in front of the fireplace inviting a sit with a good book, or maybe even a nap.

Alpert used wall treatments to define the moods and roles of various rooms in the 8,500-square-foot house. Sand-toned raffia wallcovering provides a casual and textural backdrop for the Nancy Corzine “Watermill” bed and “Valmont Lounge” settee. French doors open to the pool deck.

A departure from the blue-and-white palette of the rest of the house, the guest room has a more neutral palette with shades of brown. Four framed etchings hang above the brown linen headboard. The bed is dressed with crisp white linens with brown detailing.

A 4,000-square-foot two-story addition was completed in 2010 to create a spacious dining room, eat-in kitchen, butler’s pantry, laundry room, and three upstairs guest rooms. A gallery-like hall with French doors opening to the pool connects the new rooms. It also forms one leg of the house’s U-shape that embraces the pool and deck area. French doors in the living room open to the mahogany deck area, too, so guests can easily spill outside to enjoy the pool, ocean air, and the green lawn that rolls toward a tennis court.

Their first addition to the home though was an outdoor pavilion for entertaining (of course) with a sitting area grouped in front of a wood-burning fireplace, a bar, and a dining spot.

Two massive circa-1850 lanterns on each side of the outdoor fireplace were scored at a Paris flea market after a quick phone consult with Alpert. “We hadn’t even built the pavilion yet but we figured we’d find a place to use them,” Dennis says. “We sent an iPhone photo to Kenneth and he said, ‘They’re fabulous, go for it.’ ”

Guests often gather around the wood-burning fireplace in an area dubbed the “lantern lounge” because of the antique fixtures.

When setting a table, Dennis artfully mixes new and vintage dishes, glassware, flatware, and linens—in his signature blue and white. “Even if we just have four people, the table has to be pretty,” he insists. In minutes, he can dress the terrace table (custom made in Italy with a blue-and-white ceramic top) with a casual combination of deep blue Tiffany chargers, Royal Copenhagen plates, Pottery Barn glassware, and antique flatware.

White wicker chairs surround the ceramic-topped table, which is just outside the kitchen. “This is our go-to table for dining when the weather is nice,” Dennis says.

“I’ve heard Dennis say he could set a table for 40 people in blue-and-white splendor without renting a thing—everything is theirs,” Alpert says. “With the table, he’s a magician.” The couple’s garage rivals any catering house, lined with shelves of dishes and tabletop accoutrements, all carefully numbered and categorized.

“I have a great love for blue and white, as you can see,” says Dennis, whose collections include Chinese export porcelain, Mexican Uriarte, Dutch Delft, and Denmark’s Royal Copenhagen.

A custom ceramic table made in Italy is set with Pottery Barn stemware, Royal Copenhagen plates, and Tiffany chargers.